When submitting code samples, your goal is to show us that you can write clear, concise, readable, and understandable code. Share code that you’re proud of and that you feel represents your abilities as a developer. There is no “right” answer here, a code sample might be a single function, it might be a single class, it might be a pull request or a patch, it might be multiple files that work together. A small-to-moderate sized pull request (100-500 lines of code) for an entire feature tends to offer a good balance.

Consider your audience when putting together code samples and guide the reader to precisely what you want them to review. If you share an entire application with hundreds of files and thousands of lines of code, it’s a safe assumption that the reviewer will not read every file, so they might miss your best work and they might see the part of the codebase that least represents your skills and abilities. Further, you likely only have about five minutes to sell the reviewer on your abilities. With specific links and good descriptions, you get total control over your code samples and you remove chance from the equation.